Protocol	Port
Domain Time II IMPORTANT: The port for this protocol must be enabled to allow sync control messages and remote management regardless of what other time protocols are used.	9909 UDP
NTP/SNTP	123 UDP
TIME/ITP	37 TCP or 37 UDP

To open the necessary ports in the Windows XP Internet Connection Firewall:

1. Click Start, and then click My Network Places.

2. Under Network Tasks, click View Network Connections. (Alternatively, you can right-click My Network Places and click Properties.)

3. Right-click the connection across which you want Domain Time to operate and click Properties.

4. Click the Advanced tab, and then click Settings.

   NOTE: If the Settings button is unavailable, ICF is not enabled on this connection and you do not need to open any ports (they are all already open).

5. Click Add to open a new port.

6. Type a friendly name in the Description box, for example, Domain Time II.

7. Type 127.0.0.1 in the Name or IP address of the computer hosting this service on your network box.

   NOTE: You can specify an active IP address of an internal computer; however, in most cases you should use the localhost address 127.0.0.1.

8. Type the port number (9909 for Domain Time II) in the External port and Internal port boxes; in most cases this number is the same.

9. Click the correct protocol type TCP or UDP (UDP is correct for the Domain Time II protocol) for the port you're adding, and then click OK.

10. Repeat this process for each additional port to be opened.